GMAT Question of the Day: Daily via email | Daily via Instagram New to GMAT Club? Watch this Video

It is currently 30 May 2020, 05:21

Close

GMAT Club Daily Prep

Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Close

Request Expert Reply

Confirm Cancel

In the correctly worked addition problem shown, where the

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

Find Similar Topics 
Senior Manager
Senior Manager
User avatar
P
Joined: 10 Apr 2018
Posts: 268
Location: United States (NC)
In the correctly worked addition problem shown, where the  [#permalink]

Show Tags

New post 03 Apr 2019, 14:00
Hi, here are my two cents for this question

AB+BA = AAC

this means that B+A = X ( Say )

Now if we add any two digits the carry forward to tens digit can be either 0 or 1

If there was no carryforward from addition then X =C, if there was carry forward from addition then X=1C

Because in tens digit of addition A+B = AA, this means that carry forward from ones place was 1. if there was no carry forward from ones place then tens place would also be C .

this means in units digit the addition of B+A leads us to 1C, where C is in the units place of sum and 1 is taken as carry forward from addition.


So A+B= X= which is two digit number starting with 1_

so we know from ones place addition that B+A = 1C

so in tens place of addition we have A+B+1=AA

1C+1= AA
so 1C+1= 10A+A
1C+1= 11A
1C= 11A-1
1C= 11A-1
For any other value of A except 1 the value of C wouldn't have ten's place as 1. eg A= 2, C= 21, A=3 C=32
So A=1 now that means 1C=10
hence C =0

Now if A=1 , we have B= 9

AB+BA=
In Ones place we have B+A= 1+9=10, so 0 remains in units place of addition and 1 goes as carry forward.

In Tens place of addition we have A+B+1= 1+9+1= 11
_________________
Probus

~You Just Can't beat the person who never gives up~ Babe Ruth
Intern
Intern
avatar
B
Joined: 30 Dec 2018
Posts: 2
Re: In the correctly worked addition problem shown, where the  [#permalink]

Show Tags

New post 26 May 2019, 00:17
AB
+BA
=AAC

11*A+11*B=101*A+C
11*(B-9A)=C
as C is a positive integer in [0,9] B-9A=0
B=9A
A cannot be 0 because A, B cannot be the same number and A, B both are +ve integers from 0 to 9
If A>= 2 B is a two digit number therefore not possible for A in [2,9]
therefore A=1 ,B=9,C=0
Intern
Intern
avatar
B
Joined: 17 May 2019
Posts: 17
Re: In the correctly worked addition problem shown, where the  [#permalink]

Show Tags

New post 05 Jul 2019, 20:03
Spunkerspawn wrote:
My solution was a bit lengthy but it worked:

AB + BA = AAC
10A + B + 10B + A = 100A + 10A + C (cancel out the 10A's)
B + 10B + A - 100A = C
B(1+10) + A(1 - 100) = C

11B - 99A = C

the only value for C that satisfies this equation is C = 0. Then B = 9 and A = 1

Answer: E


How can we know that 0 is the only value to satify the equation ? Followed a similar approach but got stuck
GMAT Club Bot
Re: In the correctly worked addition problem shown, where the   [#permalink] 05 Jul 2019, 20:03

Go to page   Previous    1   2   [ 23 posts ] 

In the correctly worked addition problem shown, where the

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  





Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne